D+/D–

2.5V(Typ)

0V

InternalReset

ReadyforSetup

SOF

ReadyforPlayback

BusReset

SetConfiguration

SOF

SOF

BPZ

BusIdle

5V (Typ)

1 AudioData

st

2

AudioData

nd

V

(Pin3)

BUS

SSPND

V

L

OUT

V

R

OUT

700 s

m

DeviceSetup

1ms

T0055-02

D+/D–

V

L

OUT

V

R

OUT

AudioData

AudioData

Last AudioData

Detach

SOF

SOF

SOF

SOF

SOF

1ms

V

(Pin3)

BUS

T0056-02

PCM2906C

SBFS037

– NOVEMBER 2011

www.ti.com

INTERFACE SEQUENCE

Power-On, Attach, and Playback Sequence

The PCM2906C is ready for setup when the reset sequence has finished and the USB device is attached. After a

connection has been established by setup, the PCM2906C is ready to accept USB audio data. While waiting for

the audio data (idle state), the analog output is set to bipolar zero (BPZ).

When receiving the audio data, the PCM2906C stores the first audio packet, which contains 1-ms audio data,

into the internal storage buffer. The PCM2906C starts playing the audio data when detecting the next

start-of-frame (SOF) packet, as illustrated in Figure 32.

Figure 32. Initial Sequence

Play, Stop, and Detach Sequence

When the host finishes or aborts the playback, the PCM2906C stops playing after the last audio data have

played, as shown in Figure 33.

Figure 33. Play, Stop, and Detach Sequence

22

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Copyright

© 2011, Texas Instruments Incorporated

Product Folder Link(s): PCM2906C